Doc Bug: actioncolumn function by name delegation to controller support

It seems that in 6.2 someone decided to add some undocumented feature to actioncolumn.

I never seen that feature before so maybe I don't give a good name for it, I call it: "function by name delegation to controller".

In other words, when you set a handler like: "handler: 'myfunctionInController'" when the handler/event is executed the method 'myfunctionInController' in controller will be executed, this also work with 'listeners' constructs, so any events.

However, it seems that actioncolumn introduced also support for some undefined number of method like isDisabled, getClass, getTip to behave the exact same even if they are not event.In other words I can do: "isDisabled :'myfunctionInController'" and that function will be called in my controller!

Can I assume that new support is there to stay and not just an accident?

Is this documented anywhere? Can you document that now (open a bug)?

How the document specify each functions that are supported?

Should I see the same feature for other component/class of the framework beside actioncolumn?

This was not by mistake, where we can allowing a string to resolve onto the ViewController is wanted for MVVM sake. Just like Ext.button.Button#handler, Ext.grid.column.Action#handler does state "Function/String" in the API docs. Now other ones like isDisabled doesn't even document that it can be a function, it says Boolean only which isn't the full story for that config.